Musculoskeletal tissues, such as bone, muscle, tendon and cartilage, respond and adapt to their local mechanical environment in such a manner as to maintain a stable equilibrium, or homeostasis. Mechanical loads are also responsible for injury to musculoskeletal tissue and are critical for the rehabilitation and regeneration of the tissue. In its broadest sense, injury occurs when the loads experienced by the tissue exceed the strength of that tissue. These loads might be traumatic, such as a direct impact or single loading event causing failure, or cumulative, where repeated loads result in damage.
During running, for example, reaction forces of 2-3 times body weight are transmitted from the ground, through the foot and into the lower limb via the ankle, knee and hip joints. The musculoskeletal tissues, particularly muscle and tendon, attenuate transient impact loads as they travels up the limb. Over the course of a 5 km run, the average runner will strike the ground approximately 3,000 times and this repetitive loading has been associated with common overuse injuries, such as patellofemoral pain, plantar fasciitis, fatigue fractures, and Achilles tendinopathy.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.